This invention relates generally to solderless connectors, and more particularly to solderless connectors of the type wherein a wire is forced into a narrow slot formed in a conductive metal plate and wherein the walls of the slot dig into the insulation and into the wire as said wire enters, thereby making good electrical and mechanical connections.
There are many connectors in the prior art utilizing the basic principle of a slot formed in a metal plate wherein the width of the slot is narrower than the diameter of a wire forced therein. When the wire is forced into the slot the walls of said slot dig through the insulation on the wire to make electrical and mechanical connection therewith.
One such device consists of a U-shaped terminal having two plate-like legs joined together at first ends thereof by a transverse section. A slot is formed across said transverse section between said two legs and extending down into the said two legs. Further, the slot is wide at the top across the transverse section to permit easy entry of a wire therein, and then narrows as the slot enters the legs of the terminal to scrape the insulation off said wire as it enters down into the slot. In this manner both electrical and mechanical connection between the wire and the slotted terminal are effected.
One disadvantage of the prior structure occurs as a result of relaxation of the metal of both the wire and the terminal, but usually mostly occurring in the wire, whether it is copper or aluminum. Such relaxation tends to loosen the wire in the slot making it easier for an unauthorized withdrawal or, in fact, a dropping out of the wire from the slot under certain environmental conditions. Furthermore, such relaxation can permit air to enter between the wire and the walls of the slot to cause oxidation with resulting deterioration of the electrical contact.
Another disadvantage of the prior art structure occurs when employed with magnet wires, particularly those which are coated with one of the newer insulations, such as polyester amide/imide coating thereover. Investigation has shown that such insulations are often not sufficiently removed from the wire in that a residue of such insulation remains between the wire and the walls of the slot after insertion of the wire, thereby impairing the electrical connection.